The answer that will save the entire planet?

About the Lecture

In 1845, the Dietz Company of New York introduced the sperm oil lantern, which nearly wiped out some whale species. A decade or so later, Dietz began to manufacture lamps using other oils, and gas lighting fixtures, giving whales a reprieve. More than a century has passed, and we’re “about to do it again,” saysDaniel Nocera, consuming a precious resource and endangering this time not whales but our world. Nocera wonders, “What will be the savior,” the answer that will save the entire planet?

He ticks off the grim details of our fossil fuel habit — how the world is rapidly moving from its energy consumption of 12.8 terawatts per year, to 28 terawatts by 2050. This is a simple calculation, Nocera tells us, requiring only population, GDP per capita and energy intensity. The upshot, unfortunately, is that though we do have enough carbon-based energy (oil, methane, coal) to last all of us quite a while, the CO2 we’re emitting may choke off our current way of life long before the end of the fuel.

Nocera advises his audience to put aside dreams that biomass or nuclear energy will give us what we need. Plaster the entire planet with crops we can convert to energy, and you’d still only get seven to 10 terawatts. And you’d “need one nuclear plant every 1.6 days for the next 45 years” to get eight terawatts of power. “There aren’t enough whales to get there in 45 years,” says Nocera.

His alternative for saving the planet is “far from pragmatism and reality.” Nocera’s ultimate solution seems almost magical: “water plus light equals oil.” The proposal is to emulate photosynthesis, the process by which plants convert the energy of sunlight to fuel. Scientists are racing to design structures that can catch light the way a leaf does, then capture the energy of this light using chemical bonds, and then somehow store this energy. Some researchers are focusing on photobiological water splitting. Nocera’s group is working “on a wireless current, an artificial leaf.” While the goal “is to see what nature’s structures tell you,” Nocera acknowledges that “if you try to place what’s in nature in a beaker, it probably won’t work.”

There’s massive urgency to working out the basic science of solar energy conversion. Forget 2050, says Nocera. “Science has got to get it done in the next 10 years, because it will take an enormous amount of time to implement”.